It is stated in Patent Document 1 that a detection terminal pulled down in a card device, and a terminal pulled up inside a card slot are employed for detecting the setting and extraction of the card device in and from the card slot. When the card device has been set in the card slot, the detection terminal touches the corresponding terminal of the card slot and pulls the potential of the corresponding terminal inside the card slot, to the ground. Upon detecting the ground potential, the card slot side starts the feed of an operating power source to the card device. When the card device has been extracted, the detection terminal thereof is separated from the corresponding terminal of the card slot, whereby the corresponding terminal is brought to a power source voltage. Upon detecting the power source voltage, the card slot side stops the feed of the power source to the extracted card device.
[Patent Document 1] JP-A-2000-99215 (FIG. 5)